The Evolution of Metal-Binding Proteins
Ioav Cabantchik and Rachel Nechushtai, PhD, DSc
“Life is nothing but an electron looking for a place to rest,” a maxim attributed to Albert Szent-Györgyi (Nobel Prize in Physiology and Medicine 1937), underscores electron shuffling as the basic chemical language of cells. That language is used by proteins that produce new substances or modify existing ones, especially those that use coordinated metals for e-transfer transducers, due to their wide redox potential. As the evolution of such metal protein structures depend largely on how new folds arise from previously existing ones, it is not surprising that a vast majority of currently existing metal-binding proteins might have common features with ancestral ones, regardless of the type of metal they bind to, the organism they come from or the associated function.
In a recent (14 January 2022 ) paper published in Science Advances (Quantifying structural relationships of metal-binding sites suggests origins of biological electron transfer (science.org)), the authors propose structures of metalo-proteins that may be responsible for the origins of life in the primordial soup of ancient Earth. The use of computational methods to define common structural features of all existing metal binding proteins led them to the conclusion that, despite structural differences, the proteins shared similar metal binding cores, often made up of repeated substructures or blocks. The surprising fact was that these blocks were also identified in other regions of the proteins, not just metal-binding cores, suggesting that such building blocks may:
- have had a single or a small number of common ancestors and
- have given rise to the whole range of currently available functional proteins (YB, Rutgers).
These studies have implications for understanding the origin of the molecules of life and their diversification, two key features in biological evolution.
posted: January 26, 2022